1. Field of the Invention
The present invention relates generally to power management, and in particular, relates to power plane control for a printed circuit board (PCB), such as a peripheral component interconnect (PCI) card useable for computer network applications.
2. Background Information
The personal computer (PC) has become very popular in recent years as a tool for accessing the Internet. Desktop PCs and laptop PCs are examples of terminals that can be used to communicate with the Internet, where in some applications, one or more PCs in homes can share an existing telephone line when connecting to the Internet.
These PCs typically use PCI components, such as controllers and transceivers in the form of chips mounted on or coupled to one or more PCBs (sometimes referred to as a xe2x80x9ccardxe2x80x9d), in order to perform various networking and peripheral device operations. Multi-layer PCBs have different portions of the needed interconnections on each layer. Some of these layers are dedicated to power supply distribution and some to ground (power supply return). The term xe2x80x9cplanexe2x80x9d is often used in reference to the various layers of a multi-layer PCB, such as those layers dedicated for power supply and ground.
Various standards specify the level of power that needs be provided to the power planes under different operating conditions. An example of these standards/specifications includes the Advanced Configuration and Power Interface (ACPI), revision 1.0b, published Feb. 8, 1999. The operating conditions that require different power levels include a full power mode, where full operating power is required, and a low power mode, where it is desirable to minimize power consumption.
To meet specification requirements for full power and low power modes, PCI board designers generally use a voltage regulator to control power to one power plane and a separate voltage regulator to control power to another power plane, if separate power planes are present. However, the use of multiple voltage regulators results in an increase in the number of total components per card. Such an increase in components disadvantageously uses up precious space on a card and results in increased costs.